BGP--

[Anukalp S]

Hello..

I have a CE router connecting two MPLS circuit both are connected to different ISP with different AS. Both are connected via BGP configi want one circuit to be primary and another one secondary. I am looking to set local preference 50 and as-path prepend over secondary circuit. I am little bit confused to work this fine in failover case. Will it be good for inbound and outbound traffic.

Pls help.

[Jose Jara · Accepted solution]

Hello,

For the routes received you influence the preference of your outbound traffic. You can manipulate this with route-maps in the inbound direction. The value of local preference by default is 100, so setting 50 in the route-map applied to the peering session with the backup will work perfectly. Another way when you have just one CE, is via weight attribute applied in a route-map or to a neighbor> neighbor weight.

For the routes you are sending you influence the preference of your inbound traffic. You can manipulate this with route-maps applied in the outbound direction. By adding prepends to your backup path, will work perfectly. However, take into account the overall design of your VPN, because you may have sites in your VPN connected to another ASN's, and your provider is using Inter-AS (NNI's) with other providers. Then, if you are using a private AS and they do remove-private-as you will lose your prepends and you may end up with asymmetric routing.

Hope this helps,

Jose.

[Anukalp S]

Thanks Jose for making this clear.